| 摘要 |
PURPOSE:To form satisfactorily an image by a condition corresponding to a density by detecting an original density, and controlling a developing voltage and a light quantity correction within a range of the density extending from the first density level to the second density level, and also in accordance with the detecting density, in a copying machine. CONSTITUTION:An intensity of a reflected light from an original is detected by a photodiode 1, and a density of the original is detected. This photodetecting signal is inputted to a computer 7. In this case, the original density is sampled by several points each by a zero crossing detection, and a developing bias value is operated by the computer 7 by referring to a density of the corresponding original point and an area of this side of sad point. Also, within a range of the original density extending from the first level to the second level, the bias value is corrected by the computer 7. Thereafter, the voltage is controlled by inputting the developing bias value to a developing drum 108, and the light quantity is controlled by inputting a light quantity signal to a lamp LA1. Accordingly, in accordance with the detected density, an image forming condition can be corrected, therefore, a good image is obtained. |
